Scanning electron microscope and light microscope investigations of pollen from an atypical mid-Eocene coal facies in Stolzenbach mine (PreußenElektra) near Borken (Kassel, Lower Hesse, Germany)

Light microscope (LM) and scanning electron microscope (SEM) investigations of palynomorphs from a mid-Eocene coal lens at the Stolzenbach brown-coal mine (“Borken brown coal field”) yielded a remarkable microflora assemblage, with 76 pollen and spore taxa, dominated by monolete fern spores. Numerous pollen and pollen clumps of Myrtaceae and Salicaceae might represent in-situ growth of these families, which were associated with pollen of Aralia-type, Eotrigonobalanus spp., Flueggea-type, Nyssa-type, three Pentapollenites taxa, and Spinaepollis spinosus, plus many others. Ericaceae such as Erica-type, Kalmia-type, and Rhododendron-type pollen are described from here for the first time; the last represents the earliest known occurrence of the genus. Additionally, five tropical south Asian Sapotaceae taxa (Mimusopeae- and Isonandreae tribes), and one tropical South American bombacoid Eriotheca-type occur. Several previously undescribed pollen taxa for the Eocene have been found; some are amongst the oldest examples of these pollen taxa: the Nuphar-type pollen represents the earliest occurrence in Europe and, whilst the Acalypha-type and Trochodendron-type are the oldest pollen occurrences in general, the Viburnum-type, affiliable to Viburnumclemesiae probably represents a tropical south Asian lineage.